I have heard that meat consumption is very bad for the environment, because the animals generate a lot of methane. Is this true, and, if so, how can we limit meat consumption while remaining healthy? Would we need to stop eating meat altogether, or would limiting it be enough? How much meat should I eat each week?
Anonymous
As I mentioned in the Essential Answer, most livestock in the developed world comes from large operations. But meat is meat, right? Can raising animals in one way versus another really make a difference? It turns out that it can, and in a big way.
INDUSTRIAL FARMING
Industrial farms generally consist of “confined animal feeding operations” (CAFOs) where large numbers of animals are raised in small, enclosed spaces. Rather than feeding on pasture and forage—their natural diets—animals in CAFOs eat soy and grains including corn, sorghum, oats and barley.
These farming operations are extremely efficient—animals grow larger, and do so faster than they ever could in traditional agriculture. Even so, there are serious problems with the system that need to be weighed against its advantages. The use of grain for livestock feed is problematic not just because of the environmental consequences of its production discussed in the Essential Answer, but because feeding these grains to animals diverts them from human diets, leading to less food available overall.
Also significant are land and water use—growing enough feed for the 56 billion land animals raised for human consumption annually puts a serious strain on resources worldwide. When livestock consumption goes up, producers need more feed grains, and that increase in demand prompts an increase in the price of cereals (yes, this is one of the big reasons food prices have been so high recently). When the price of cereals rises, farmers have more incentive to grow those crops, pushing existing land for more production, or expanding into new areas. Beyond altering biologically significant land, deforestation results in huge carbon emissions as new land is plowed and trees are cut and burned to make way for crops, releasing the carbon dioxide stored in trees.
Of course, many of these environmental issues are associated with all cereals production, whether or not it is used as livestock feed. But eating livestock is a much less efficient way to get nutrients than directly consuming the grains on which they are fed—it takes almost 20 pounds of grain to produce a single edible pound of beef according to Vaclav Smil in his 2000 book Feeding the World, A Challenge for the 21st Century. As a result, more land needs to be cultivated than if the crops were eaten directly. Conversion efficiencies vary among animals—chicken and pigs are both better at converting feed to edible weight than cattle are. This is one of the main reasons that beef results in more emissions than other kinds of meat.
The other reason is enteric fermentation, the ruminant digestive process that produces methane. Since cows and sheep give off the greenhouse gas as they eat, but non-ruminants like pigs and chickens do not, the environmental consequences of cow/sheep production are much worse than those of other animals. Even worse, the EPA found that methane production is enhanced when ruminants are fed the unnatural grain diet, meaning the climate-change consequences of factory farming are even greater, though the validity of this concern is still being debated.
There are other problems with CAFOs, as well. Keeping large numbers of livestock in a small space and feeding them grains they have not evolved to digest inevitably has consequences. The animals are often prone to disease, so their diets are supplemented with antibiotics and growth hormones. Antibiotics are also used to promote growth in livestock; the mechanism by which this occurs is uncertain, according to the FAO, but may involve the suppression of intestinal bacteria. This has caused concern about the health consequences of consuming meat containing antibiotic and growth hormone residues, as well as the possibility that the frequent use of antibiotics will help breed resistant strains of bacteria. Thus far, the FDA has released only voluntary, unenforceable guidelines for antibiotic use in CAFOs.
The concentration of industrial livestock systems has implications for the environment too—most significantly, waste production. When livestock are raised on farms that produce crops, manure can serve as fertilizer; when they are raised far from crop production, though, their waste has nowhere to go. Its disposal, much less regulated than the disposal of human waste, often contaminates water sources in surrounding areas.
THE ALTERNATIVES
Not all modern meat production is quite this bad, and some alternatives are markedly better for the environment than the industrially raised fare. For meat to be labeled as organic, for instance, it must have been raised under particular conditions. Some of these conditions include that the animal never received antibiotics or growth hormones and that it ate only certified organic grasses and grains. Other stipulations involve animal welfare, including that animals designated as organic had some amount of outdoor access. Unfortunately, while some of the health concerns associated with conventional meat are alleviated by organic farming, most of the pressing environmental concerns remain. Many organic livestock operations only differ meaningfully from conventional producers in their use of certified organic feed—but with fairly loose guidelines on what constitutes organic feed, this change is not as impactful as many would hope.
Some organic meat production goes further to distinguish itself from conventional production. One key way this is done is by allowing livestock to feed on grass, reducing (though likely not eliminating entirely) the need for feed and therefore its environmental consequences. Of course, even this doesn’t resolve the methane emissions associated with normal digestion, though it mitigates some of the other environmental issues associated with feed production. And there are efficiency tradeoffs with this form of farming—animals take longer to mature and require much larger land areas than in the more concentrated systems. As a result, grass-fed meat can be more expensive than the grain-fed alternative.
Even organic meat is not enough for some meat producers and consumers, who aspire to go “beyond organic.” A standard bearer for such production methods is Joel Salatin, owner of Polyface Farm. The farm has been lauded for its successful efforts to reproduce the natural ecosystems in which livestock function as closely as possible. Animals are fed on forage, and pastures are in turn fertilized by manure, with the goal being efficient and sustainable agriculture. In exchange for such high standards of sustainability, customers must be willing to pay a large premium—prices for meat from operations like Polyface are much higher because they are less “efficient” than large-scale farms. Of course, there are high (environmental) costs associated with conventional farming, as well—the main difference is that these costs are borne by society as a whole rather than just those who consume the product.
Ironically, another potential alternative to industrialized meat is a truly industrial product: laboratory-grown meat produced from stem cells. Scientists have had relative success with the technology so far, with the first stem-cell burger expected to be ready by October 2012. Since the cells multiply rapidly, stem cells extracted from a single organism could produce on the order of a million times more meat than the original animal could. While the technology is promising (no more methane!), people might be uncomfortable eating meat grown in a test tube. And the fact that the first test tube burger will cost upwards of $300,000 means that the technology is prohibitively expensive . . . for now.
MAKING CHANGE
Can individual meat-eating habits make a difference? Using numbers from the EWG study mentioned earlier, for an average person, not eating meat just one day a week saves 2.27 kg of CO2 equivalent per week, or a total of 188 kg of CO2 equivalent per year. (CO2 equivalent measures the aggregate impact of greenhouse gases using the equivalent amount of CO2 that would have the same impact. That way, we can look at the combined effects of different greenhouse gases.) That’s the same as driving 250 fewer miles in the average U.S. passenger vehicle. And if the entire U.S. observed Meatless Mondays? More than 36 billion kg of CO2 equivalent would be saved, comparable to 80 billion fewer miles driven. Even greater savings could be achieved by cutting out more meat or replacing conventional meat with alternatives. While it might not be enough to single-handedly (or single-hoofedly) resolve climate change, it’s a step in the right direction.
